I'm getting good accuracy with both IMR4064 and RL15 under a 140 Nosler BT. Any experience on which powder is less temp sensitive?

Pretty sure I read a while back the military was spec'ing re15 in 308 ammo.
But, if it was to thwart dessert heat I'm not sure if its still good when temps go sub zero.
I've also read that some powders can be very temp consistant in a certain cartridge but not so much in another. If re15 is a winner in 308 I'd like to "think" it would be good in 708.

Varget...oh sorry. That wasn't an option. It does well in my 7-08. I'm interested in hear other replies on those two powders.

Ramshot Big Game is reportedly fairly temp stable and about the right burn rate.

DF

Did a Google search using either powder and the words "temp sensitive" and tons of posts pop up. From what i read it would appear both are sensitive as you go warm to cold at a rate of about 1 fps per degree of temp loss.
Here's just one of many many reads....

http://forum.snipershide.com/snipers-hide-reloading/243262-rl-15-imr4064-temp-sensitivity.htmli

If you can find some, try H4350 between 46-48 grains.

Yeah, those Australian made Hodgdon Extreme series powders are about the best for lack of temp sensitivity.

Tried Big Game with 120's and 140's. Great speed, but accuracy was lacking.

I can't seem to find Varget and it would be a good temp stable powder.

CFE-223 is in the right burn range. I have some but have never used it in a .308. It's sort of a military type powder. Does anyone know how its temp sensitity rates?

DF

If you can find AR Comp... its like RL 15 but Temp Insensitive... burn rate is a hair quicker, but since Reload data is conservative, Rl 15 data has worked well for me so far...

Out of 9 responses 7 fail to answer the OP's original question.
??????

Why do members who do not know the answer feel they have to jump in?

Jim

When Hodgdon came out with their extreme powders they made a mistake in their "take the extreme tour" presentation.

They showed how great Varget was and in the same chart they showed IMR 4064 which had a 46 fps velocity change from zero to 125 F.

See page:
https://www.hodgdon.com/smokeless/extreme/page2.php#top

Don't know about RL-15's temperature sensitivity.

My vote is for 4064. My 7/08 loves 41.0 grains behind a 140 grain Ballistic Tip. That load yields some amazing groups for me. Have not had any problems with temp sensitivity with that load.

Not too bad. Thanks for posting. My temperature swings are not that extreme, so it looks like I'm fine with IMR4064. Mid 20's in winter through upper 90's in summer.

I'm running IMR 4064 but have not tested it throughly in "extreme" temps. Thus far it shoots great from 60-95 degrees. I plan on running this load for deer in Nebraska where temps can be frigid but usually around 30's.

Some of the RL series of powders are a little sensitive to temperature change. RL 15 is not. It is right in the ballpark with Hodgden's Extreme powders.

I have IMR 4064 and use it in several calibers. Great powder.

Hey, it's the Fire for goodness sake...

DF

Reloader 15 works great in my 7mm-08 with both 120 gr. and 140 gr. bullets. At temps from 15 degrees up to about 90 degrees, I have no appreciable changes in POI or in chronied velocity. Any variation is no more than I get between strings on the same day. There's my two cents worth..........

Not bad mouthing anyone's favorite powders, and I shoot all the above mentioned powders at one time or another. But if you haven't tried RL 15 in a 7mm-08, you may be missing out on a good shooter. I have owned five; a Ruger M77, a Remington M700, a Kimber 84M, and two Cooper Excalibers. RL 15 worked the best in all five. I don't know the odds of that happening, but I speak the truth.

Reloder 15 is indeed one of the less temperature-sensitive Alliant powders. It wasn't always, but maybe a dozen years ago was reformulated for U.S. military use. After that it was far less temp-sensitive than IMR4064 has ever been.

However, one thing that many if not most handloaders don't realize is that temp-sensitivity depends on the application. Even the Hodgdon Extremes are at their best in cartridge/bullet combinations that fit into their optimum burn-rate range. But Reloder 15 is very good with the bullets most hunters shoot in the 7mm-08. It probably wouldn't be as stable with 175's or even 160's.

Lastround, I need to try that RL-15 out! I also wouldn't mind throwing some in a 308 win case to see what it does?

I have seen good results with both RL 15 and Varget in the 308, even though I haven't had great results out of Varget in the 7mm-08. I've not used either powder for anything heavier than the 165/168 gr. bullets. It may have the same tendencies that Mule Deer referenced in that it may be better with the lighter weights. I never load anything above 140 gr. in the 7mm-08, nor the 165/168 in the 308. Just me........

Esox, I have kind of kept with the tribulations you had with your 7mm-08 about a year ago. I hope if you try RL 15, it will work as well as it has for me. You may even find that you can go back and find something good with those 120 gr. bullets. Good luck to you.

Hey I appreciate it lastround! The H414 with a max load under a 140 TTSX is shooting sub moa. Also found a great load using IMR 4064 with a 130 speer load while very mild I think it would do well for deer/hogs? Waiting to test out my hypothesis. I am very tempted to experiment with RL 15, if for nothing else for my 308.

My limited use of Varget in a 308 proved to be inconsistent. I used this with mostly a 175 SMK. I'm still searching for a good paper punching load as well as a hunting load for that particular rifle.

Has anyone used the latest wonder powder, IMR 8208 XBR?

DF

DF,
I've loaded it in 223 and 7mm-08. Got good velocity in both, accuracy was good in the 223, but not consistently good in the -08. I really wanted it to shoot in both but RL-15 was the winner again in the 7mm-08. At the time, the LGS had lots of 8208, but no RL 15. Your results may vary.

I fail to understand why people treat the relationship of temperature and velocity as a linear one (i.e. x fps change per degree of temp change). If you had enough data and plotted that data out on a graph, they would form an inverted S-shaped curve, not a straight line, something like this:



The less sensitive the powder in question is to temperature, the flatter the curve. ALL powders respond to extreme hot and cold temps with velocity changes; it's just that the "temperature-insensitive" powders do it to a lesser degree.

To the OP: this is a long answer to a simple question, but if none of Hodgdon's Extreme Powders work for you, go with RL15 as others have recommended.

I personally have not, BUT, the guys that run the ranch I whitetail hunt on, in the TX Panhandle, have extensive use with it. Their sniper training buddy T. Hodnett and co claim it is the most temp stable powder the have ever used in their .308's, and that's saying something since they train snipers from all over the world. They have the best luck with it with heavier bullets though, 168g+.

There is NO one answer for the OP. Given the case, and the bullet weight, I would hazzard a guess that Varget would do the best.

What no one seems to comprehend, is the basic theory of operation about this whole notion.

1) If you actually read Hodgdon's own testing, MOST of the "advantages" are statistically no different than another choice. There are several other problems with their info, but the majority of the time, Assuming they actually have a large enough sample size, there is no difference.

2) What they don't tell you, and is positively the truth; the "temp insensitivity" thing is NOT a universal property. A Powder can have coatings that will lend it to such a state, based upon a very specific set of conditions only. The problem is, that other than some assumptions based on Hodgy's testing, they won't tell you what those parameters are. For example, Varget was built to be extreme in the 308, with a 150gr bullet only.

There has been some very good work (good methodology and science) done by Dr. Denton Bramwell on this very thing. While there is no doubt there is a difference in the 308 with the conditions listed, is the difference tangible to the average shooter? His work has also further proven that the properties are not universal. His testing in the 223, has shown Varget to be a rather steaming pile of crap, when compared to even old ball powders. Doesn't mean that a powder won't shoot good groups, but don't think the property is universal. Even Western speaks to this specificity on their site.

Another side effect of the coatings used in the Extreme series, is the development of Hard Carbon fouling. Again not an unknown side effect, and it accumulates faster in smaller bores.

The military doesn't call a surplus re-seller/blender for powder either. They call the manufacturers and order train loads. While a powder may or may not be the non-canister grade parent of a powder, they don't load Canister grade powders that are known to the reloader.